In a number of prior art applications, it has been found desirable to hold a door in an open position notwithstanding substantial forces acting on the door tending to swing it from the open position. One example of such an application is that of the door for a cab of a vehicle, such as an earthworking vehicle.
In the normal use of such earthworking vehicles, such as tractors, etc., the cab may be air conditioned. It has been found, however, that the operator may prefer to operate the vehicle with the air conditioning apparatus de-energized such as during temperate weather conditions. At such times, the operator may ventilate the cab by opening the cab door and various means have been provided for maintaining the door in the open position during such use.
One excellent example of a door holding means for such use is illustrated in U.S. Pat. No. 4,035,016 of John S. Ricca, which patent is owned by the assignee hereof. The apparatus for holding the door in the open position includes a crank having a handle and an eccentric arranged to hold the door against a stop. The structure includes a resilient linkage and means for limiting rotation of the crank to allow an over center action whereby the resilience of the linkage provides a firm holding of the door against the stop.
In another form of prior art structure for holding a door in an open position, catch mechanisms are provided at the top and bottom of the door. However, at times, relative motion occurs between the cab and the platform so as to cause twisting of the door held by the catches.